David Cameron repeatedly said in the run-up to the EU referendum he would not resign in the event of a Brexit.
The prime minister insisted that regardless of how the country voted he would stay on until the end of the current parliament when he is due to hang up his boots in any case.
Earlier this month, he suggested he would reshuffle his Cabinet to give greater power to Eurosceptic Conservatives if the UK voted to leave.
But now that scenario has become a reality, the Tory leader will be under pressure to step down immediately.
It’s doubtful a change of personnel will be enough to silence the chorus of Brexiteers baying for his blood.
As head of the Remain campaign, Cameron put his neck on the line and it’s likely he will have to go.
While he has previously proved a skilled operator when backed against a wall, this is one bind from which he probably won’t manage to break free.
That said – keen to salvage what credibility he can – he may try to fight for his position.
Either way, he will go down in history as the PM who led Britain to the EU exit door.
Like Tony Blair and the Iraq War, he will not be able to escape his legacy.
Moreover, if he remains in the top job, Cameron will have to negotiate the agreement to withdraw from the EU and endure all the humiliation that brings.
There’s an upper limit of two years to the process, but it can be extended with the consent of all member states and so could go on longer.
As well as the personal ramifications for Cameron, we’re about to read the next chapter in the tale of the Humpty Dumpty Tory party, now facing the not easy task of putting itself back together again.
Whether or not the PM bows out voluntarily, expect a leadership challenge.
A ballot will be triggered if 50 MPs write letters of no confidence to the chairman of the 1922 Committee of Conservative backbenchers.
Then it’s every man and woman for themselves as the leading Vote Leave comrades morph into each other’s rivals.
And don’t be surprised if someone unexpected throws their hat into the ring too.
